Pneumatic hammer.



G. P. DUVAL H. MUDEEMOTT.

Punuumo anun.

ATTUHWEYS- C. F. DUVAL H. MODERMOTT.

PNBUMATIO HAMMER. APPLIoA'rIon rum JULY 15, 1910.

L r m n .w s oo u T N 1 m0. M van V00 .n E WEG .m n J u w 3 L m 2 D..

Patnted July 18, 191.1.

a annu-sanar s.

C. F. DUVAL H. MGDERMOTT.

PHEUMATIU HAMMER.

. Arruurnon nun JUL: 1s, mo. 998,477.

ATTURIIEYS UNITED 'STATES CHARLES F. DUVAL AND HENRY MODERMOTT, 0F- LEADVILLE, COLORADO PNEUMATIC HAMMER.

Specification of Letters Patent.

Patenten July 18, 1911.

Application filed July 15, 1910. Serial No. 572,121.

To all whom fit may concern:

Bo it. known that we, CHARLES F. DUVAL and llicsin' MoDnniio'rr, citizens of the' United States, and residents of Leadville, in the county of Lake and State of Colorado, have invented certain Improvements in Pneumatic llaiiiniers for Rock-Drills and other Machines, of which the follwing is a speciliention.

()|:iiinention is an improvement in that einen ot peri-usare tools which are used for drillingr roi-k or other material, also for rivetine. chipping metal, calking boilers, and olla i' analogous operations.

di-tin; fuialiing feature of our invention is the construction and arrangement of the liuinnier proper, or the reci rocating portion of the tool by which bows are sti-nek, it being protected by a casing and reciprocating without frictional contact therewith. and having: a chamber which receives a fixed guide that is provided with inlet and exhnird ports and surrounded by an annular, niniiuallieontrolled valve having: similar poi-1s. alien-hy [he admission ahd exhaust of the motivil [luid is governed in such manner as to produce at will variable strokes of t'lic hammer' which is a result of much importance in tools of this class.

Another important feature is the cushionina,r of the liaiiinier on the return Stroke.

The invention further includes other features as hereinafter indicated.

In the accompanying drawings, Figure l is a lide view of .our improved tool. Fig. is acentral longitudinal section of the dame. Fim 3 is a cross section on the line Bml ot' Fig. 2. Fig. 4 is a longitudinal scction oi the tool corres ending to Fig. 2, save that the hammer is siown in striking position. Fig. 5 is a perspective view of the annular valve provided with-inlet and exhaust porta. Fig. is a perspective view of thc -f hammer guide provided with ports. Fig. 7

is a cross section'on the ,line 7-7 of Fig. 2. Figs. 8, t). `10 and 11 arefpross sectional views iypresenting different adjustments and positions of the annular valve with reference to the abutment, on .which the hammer is guided ii. its reciprocation.. Fig.' 12 isa longitudinal sectional view of an extensiblefeed. Fi?. 13 is a longitudinal section of a vmodified rm of the pneumatic hammer or tool.v p

Referrin particularly to Fig. 1, the numeral 1V in icates the body of the cylindrical casing, and 2, the hollow reciprocating haminer proper which the casing incloses and .|`)rotec ts, while 3 indicates a fixed 'guide on which the hammer slides without contact with the casing` and 4, the annular rotatable valve which controls: admission of the m0- tive fluid to the hammer.

The inner 'end of the casing 1 is provided with a radial flange ,1a which is secured by bolts 5 to a cylindrical block 6 and a flanged nut 7. Said block 6 is bored to receive the hammer guide 3, and the flanged nut 7 isiV screwed on the inner end of the'guide, as shown. The mit is provided with an inter-` nal socket 7Il that adapts it for attachment See Fig. 12--thc same consisting in this case of a series of telescoping-Sections adapted for cxtension by. air pressure, and Serving in practice as a rest or support for the pneumatic hammer iis-a whole.

The hollow hammer 2 has a hollow truncated head and a thickened butt 2 which is secured to it byineansof a screw-joint. This construction favors lcon venien't "assemblage of the parts, besides `etl'ecting economy in construction.

enlarged, or has greater diameter than its body, which is 4provided with a seriesof radial inlet ports 12, 13 and 14 andan' exhaust port 15, allot-which communicate or outer end of the guide.

The annular valve -l has a series of ports 12, 1.3, 14, and 15a-sec Fig. 5and is provided at 'its butt or inner end with a radial flanged which, as shown in Fig. 1, is ,pro-

valve may be adjusted rotatably yto control in practice,.beiner attached at 20.-.(Fig. 1)..

sages 17 vand 18 and annular chamber or space 19 is constant or always the same as with a central bore 1,6 that opens at the vheady vided with a radial'haiulle 4", by which the" admission and exhaust. of the motive fluid.k The latter is adtiitted first to a smallfan. nular chamber 1T forinedin the'hlock (Sand:V surrounding the inner end-of the hammer guide. From such chamber. apassagel yleads forwiiril or `outward in' the `guide 3d and .opensvat'* itc outer-and into an annular space 19 that is foi-ined .between .thctlarige l and hammer 2 andgthe =thickenedbut-t; 2fof. the latter and the head ot lthe guide.

The motive fluid is conducted to the itubei by a flexible hose in the naualwathe same,-

Thepressnre of the motive fluid inthe-:pas--` toa device commonly known as the feed The guide 3 is cylindrical audits head is in tue Hexible hose and the tank or boiler with which it is connected. It is apparent that since this pressure acts against the shoulder of the hammer guide and the butt 2'L of the hammer, the tendency is to retract the hammer and hold it retracted until such ressure is overcome by a superior one, which 1s always lthe case when the motive fiuid is admit-ted by any one of the live ports 12, 13, 14, so as to act against the head of the hammer. In such case, owing to the greater area of the hammer head, as compared with the shoulders of the hammer butt, the effect is to drive the hammer forward and into contact with the strikin pin 11 with a rapidity and force correspon ing to the pressure of 1the motive fluid.

As shown in Fig. 5, the orts or openings 12, 13, 14 and 15 in t e sleeve valve 4 are arranged upon a spiral line, so that no two of them shall communicate simultane-.

ously with the corresponding ports 12, 13, 14, and 15 in the hammer guide.

As shown in Figs. 2, 8 and 9, the valve head or butt 4'* has an interior arc slot 2l with which a r1 ht angular Apassage 22 in the hammer. guie 3 communicates. When the valve is 1n the neutral position shown in Fig. 8, as when the tool is not in use, the bore or passage 22 is in communication with another 23 which is formed in the valve butt. From the right an lar bore 22, another 24-see Fig. 1-lea s to the socket 7* where the feed 1s attached. Thus, in the position of the valve shown bv full lines (Fig. 8) the air or other fluid which presses upon the feed durin the operation of the tool is allowed Ato ex aust through the port 23, thus relieving all ressure on the feed so that the tool may be removed from its position or otherwise manipulated vas required. The arc slot 21 communicates by a lateral passa e with the lon 'tudinal port or passage 18 ormed in the -ammer guide 3 and communicating with the annular 4space or chamber 19, as before described.4

As before intimated, Fig. 8 illustrates in full lines the neutral positlon of the valve,

and the same position is also illustrated inv Fig. 2. Figs. 9, 10, and 11 illustrate dilierent ositions according as the motive fluid is a mitted through one or another of the three ports 12, 13, and 14 in the hammer guide. The full lines in Fig. 9 illustrate the first position; that is to sa when the valve 4 is adjusted by means o its handle 4" to bring the port or opening 12 of the valve into conjunction 'wit the port 12 in the hammer guide. As before stated, there is a constunt pressure of the -motive fluid in the annular chamber 19, and, therefore, when the valve is adjusted as stated, this pressure acts instantly throu the bore 16 of the hammer guide andg forces the hammer agaixgst tuhe striking-pin ll-see Fig. 4. Be-

fore the hammer strikes, its butt 2* has covered the live port 12* in the valve and conseuently the motive fluid acts expansively uring the final movement of the hammer. The instant the hammer strikes, the motive fluid is exhausted through ports 15 and 15 which are then uncovered and the exhaust is into the outer air through port 25- Figs. 2 and 5. All pressure upon the head of the hammer being thus relieved, the pressure of the fluid in the annular chamber 19 acting against the butt 2 of the hammer forces the lattei` back until the ports 12' and 12 are a ain uncovered, when the operation before escribed is repeated, the hammer being lforced forward and giving a stroke as before. Thus, the hammer oscillates rapidly and gives a series of rapid blows on the strikin -pin. If, now, the valve 4 be turned4 urt er, or into the position shown by full lines in Fig'. 10, its port 13'L will register with port 13 of the hammer guide and the hammer will again be forced forward to strike upon the pin 11. Similarly also the exhaust 15 being uncovered, the air or other fluid is exhausted from the hammer and the pressure of the fluid in the annular space 19 acting against the hammer butt 2, again lforces it backward until the ports 13L and 13 are again uncovered, when the hammer stroke is repeated. The operation is precisely the same with reference to the third position illustrated in Fig. l11, where ports 14n and 14 in the valve and hammer guide, respectivel are put in conjunction. It will be seen t at the movement of the hammer always covers the ports through which the motive fluid is admitted to the bore of the hammer guide to act upon the hammer head before the hammer comletes its stroke, so that the latter is effected y the expansive action of the fluid. It will be further seen that when the hammer finishes its stroke, the exhaust ports are uncovered in every case. It wlll be understood that the valve remains fixed or held by friction in the position to which it ma be adjusted, whether thatbe neutral, as in ig. 8, or the different working positions shown in Figs. 9, 10, and 11. In other words, thevalve is only adjusted when it is desired to vary the stroke or stop the operation of the feed.

l From the foregoingv description, it will be apparent that the stroke of'the hammer is varied in length, rapidity, and force accord ing to the distance of the valve ports 12,

13, and 14 from the head of the hammer. y

In other words, when the motive fluid is ad' mitted through the-ports-12IL and' 12 nearest the hammer head, in the return movement of the hammer the butt2 uncovers such ports sooner than it could uncover the other ports, and consequently -the motive fluid under pressure is again. admitted through the ports .latter communicating 12EL and 1Q, as before, and the operation of the hammer is repealed. Il the valve be adjusted to admit motive-fluid through the lower ports lflt and ift, ille hammer is allowed 'to return or slide back a longer distance before its butt El can. uncover said ports. '1`lie1efore, when the motive fluid is admitted through the outer port, the operation of the hammer is rapid but the strokes are comparatively light, and when admitted through the rea r ports ll-2l and 1l, the` stroke ofthe hannner is longer and heavier; while if the motive fluid be admitted through the intermediate ports 13a and 13, the stroke will be intermediate in rapidity and force. In brief, when the motive Huid isadmitted through the outer ports, the nunnentum of the hammer is least and when admitted through the rear ports in the valve and hammer guide, the momentum is greatest, and the blows vary accordingly both in rapidity and force.

In the modification shown in Fig. 13, the hammer ,fluide is constructed hollow throughout, and the valve is arranged within it instead of surrounding it as in the .-onstruction first described. The valve is provided with a radial handle as before, and the hammer guide has inlet and exhaust passages, as in the. first case. While the valve is construct ed with longitudinal grooves 28 and 18, the with the annular chamber 1E) and with a passage leading to the socket where the fee/di may be ati tached.

The operation will be apparent without further description.

We claim:

l. A. pneumatic hammer comprising a chambered hammer proper, a fixed guide on which said hammer reciprocates, the same being provided with lateral inlet 4and exhaustports. and a valve provided with corresponding ports and adapted for adjustment to admit motive fluid to aetuate the hammer.

2, A pneumatic hammer comprising a hollow hammer proper, a fixed `afuide on which the hammer reciprocates, a rotary valve having,r inlet and exhaust ports corresponding with those of the hammer guide, the hammer serving in its reciprocatious to cover and uncover the ports whereby the hammer is worked expansively, substantially as described.

3. A pneumatic hammer comprising a hollow hammer properfa fixed guide therefor provided with a series of ports, a rotary valvehavinp; correspol'iding ports so located that when the motive fluid is admitted to a ,guider port it is cut ofi" from the others 'whereby the hammer may be worked with a variable stroke, substantially as described.

4. A 'pneumatic hammer comprising a hollow handle proper, a fixed guide on which the same reciprocatcs, a rotary valve applied to the'guide andboth having inlet and. exhaust ports adapted to be brought into coincii'lcnce by adjustment` of the valve, the ports of the valve being arranged out of alinement in such manner thatany one may be brought into register with a corresponding,l one in the guide, substantially as described.

A pneumatic hammer comprising an outer casing, a fixed guide arranged within and concentric with said casing, a hollow hammer adapted to slide on the guide, a rotary valve applied to the guide, thertwo having inlet and exhaust ports which are adapted to be brought into coincidence by adjustiuent of the valve, the guide also havini;r a longitudinal bore leading to its outer end for conducting motive tluid into contact with the hammer head, substantially as described.

(i. A pneumatic hammer comprising a casing, a hammer guide fixed concentrically within the same, a hollow hammer adapted to slide on the guide, the latter havingr an enlarged head and reduced body and inlet and exhaust ports communicating with a longitudinal bore leading to the head of the guide, a rotary valve applied to the guide and having corresponding ports adapted to be broughtinto coincidence with those of the guide, the hammer having a butt portion provided with a shoulder whereby an annular chamber is formed between the same and the head ot' the guide, a port for motive iuid formed in the guide and communicating,r with such annular chamber whereby upon adjustment of the valve te admit motive tiuid under pressure to the head of the hammer, the latter is caused to give a stroke, exhaust then takingr place and the pressure of the motive fluid in the annular chamber acting against the shoulder of the hammer serves to return it to the original position, substantially as described.

7. A pneumatic hammer comprising a casing, a hammer guide arranged concentrically Within the same, a hollow hammer adapted to slide on said guide, and a rotary valve applied to the latter, both guide and valve having inlet and exhaust ports adapted to be brought into coincidence, the inlet ports of the valve being so arranged that only one at a time can bebrougrht into coincidence with a port in the guide, the arrangement of the exhaust port with reference to the head of the guide being such that as the hammer makes its stroke, it uncovers the said port, and the chamber being provided for the motive fiuid wherein it is under constant pressure and acts against the rear portion of the hammer having a less area than the head of the same, substantially as described. l A

8. A pneumatic hammer comprisingr a casing, a guide'fixed concentrically therein,

a hollow hammer adapted to slide on the guide and having a rear shoulder comprislng less` area than its head, the guide being provided with inlet and exhaust ports, a rotaryl valve similarly provided with ports over which the rear portion of the hammer is adapted to slide so as to cover and uncover them, as described, a chamber being formed around the valve to 'which the motive fluid under ressure has access at all times, a differential pressure being thus established, one tending to retract the hammer and the greater servlng to actuate it for a stroke, substantially as described.

9. A pneumatic hammer comprisin a casing, a fixed hammer guide therein, a ollow hammer reciprocating on said guide, a rotary valve applied to the guide and both provided with inlet and exhaust ports adapted to be brought into coincidence upon rotation of the valve, a. base block to 'which the casing is secured, the same beinfg provided wlth an inlet for the motlve uid under pressure, a longitudinal port in the guide communicating with such chamber, an annular s ace being formed around the valve and gulde within the hammer to which the motive luid has constant access under pressure, substantially as described.

10. A pneumatic hammer comprising a casing, a fixed guide therein and provided with inlet and exhaust ports, a rotary valve similar] y provided with ports, a hollow 11ammer adapted to slide on the guide and inclosing a portion of the valve, the guide having an enlarged head and the hammer a rear shoulder between which two parts a chamber is formed, a supply port communieating therewith through which motive Huid is supplied und`er constant pressure, the valve butt bein provided with an areslot adapted when t ie valve is ina certain position to communicate with the aforesaid supply port, another port formed 'in the abutment and communicating with the socket adapted for attachment of the feed, whereby, when the valve is in Working position, pressure is constantly applied to the feed and when the valve is in the neutral position, the pressure is relieved, substantially as de scribed.

CHARLES F. DUVAL. HENRY MGDERMOTT.

Witnesses for Charles F. Duval:

SoLoN C. KEMoN, Amos W. HART.

Witnesses for Henry McDermott:

SonnN C. MOWBERG, J AMES T. HOGAN. 

